Method of manufacturing synthetic bristles for brushes



1943- J. J. GREGORY 2,455,759

METHOD OF MANlj'FA'CTURING SYNTHETIC BRISTLES FOR BRUSHES v Filed Ayn-1.1 28, 1944 2 Sheets-Sheet 2' Jou/v .1 619E601? Y Patented Dec. 7, 1948 I METHOD OF MANUFACTURING SYNTHETIC BRISTLES FOR BRUSHES John J. Gregory, Creighton, Pa., assignor to Pittsburgh Plate Glass Company, Allegheny County, Pa., a corporation of Pennsylvania Application April 28, 1944, Serial No. 533,206

Claims. (Cl. 30021) This invention relates to the manufacture of synthetic filaments and it has particular relation to methods of measuring, cutting and preparing synthetic filaments adapted to be employed as bristles in the manufacture of brushes, or for other purposes.

The invention herein disclosed constitutes a continuation-in-part of my copending application Serial No. 499,264, filed August 19, 1943, now Patent 2,356,841, of August 29, 1944, for Filament cutting apparatus.

One object of the invention is to provide an improved method of cutting synthetic filaments to predetermined lengths.

Another object of theinvention is to Provide an improved method of cutting filaments that are tapered at intervals and preparing them for assembling and further cutting to lengths according to the taper therein so as to insure the proper bristle arrangement for incorporation thereof into a brush.

Another object of the invention is to provide an improved method of cutting and bunching or bundling synthetic tapered bristles.

In one form of the invention for producing bristles for brushes, synthetic filaments are received continuously from a filament forming machine, such as that shown and described in my guided. Sincethe filaments are tapered at intervals, the variation in thickness thereof can be utilized to make and break electric contacts when the thicker portions pass a predetermined point. These contacts are connected to an electric cutting device which is operable to sever the filaments when itis electrically energized. The

relative positions of the cutting device and the guiding surface and the distance between thicker portions of the tapered filaments can be coordinated to control the cutter so as to sever the filaments regularly either at the location where they are thicker or at the location where they are thinner.

In connection with one form of the invention, ithas been found that very satisfactory results can be secured by cutting the filaments approximately at the location of their maximum thickness. Although the filaments can be extruded in smaller or larger form according to the fineness or coarseness of the brush in which the finished bristles are to be incorporated, they are, regardless of size, resilient and inherently springy to such, degree that they tend to remain straight or extended. The bristles are first cut at the location of the maximum diameter 2 or thickness and can be collected and bound in bunches or bundles of double length with the smaller portions receiving the binding tape, or the like, so that the butts or larger cut portions are disposed at opposite ends of each bundie. In this way the location of the smaller portions are readily discernible and the cut and bundled bristles can be laid aside or stored pending their incorporation into brushes. Since the inner areas are together each bunch can be held thereby, and if there are any broken pieces or scraps of filaments which are to be discarded they can be removed by combing them out or by any other suitable method. when the bristles are to be incorporated into brushes the bundles are cut at the bound thin portions by shears, or otherwise, and their. proper relation maintained. t

In the drawing:

Fig. 1 is a diagrammatic elevation of a filament cutting apparatus; Fig. 2 is a fragmentary elevation, on a larger scale, of electric make and break contacts with supportsthereofor; Fig. 3 is a vertical section taken substantially along the line III-III of Fig. 2 and with parts shown in elevation; Fig. 4 is a view similar to Fig. 3 with parts shown in different positions; Fig. 5 is a horizontal section taken substantially along the line V-V of Fig. 1 and with cutter structure shown in plan; Fig. 6 is a side elevation of the structure shown in Fig. 5 looking in the direction of the arrows on line VI-VI of Fig. 1; Fig. 7 is a fragmentary vertical section, on a larger scale, of a tubular guide including air directing parts; Fig. 8 is a fragmentary horizontal section taken substantially along the line VIII-VIII of Fig. 7; Fig. 9 is a diagrammatic plan of a bundie of filaments cut to double length sections; Fig. 10 is a diagrammatic plan of a synthetic bristle; Fig.'11 is a fragmentary perspective of a bundle of filaments with shears for cutting them; and Fig. 12 is a fragmentary view, similar to Fig. 11 of a bundle of bristles-after the bristles have been severed.

In practicing the invention a drum Ill is rotatably mounted upon a horizontal disposed driven shaft I2 which rotates in suitable bearings l4 on asupporting frame 15. A motor l8 having suitable reduction gearing [9 connecting it to the shaft provides power for rotating the drum.

Filament stock 20, which can be in the form of one or a group of filaments, is received from a source of supply, such as a filament producing machine described in my copending application Serial No. 459,251, above referred to, and such stock isguided over an idle roll 23 carried upon a pin 24 "in a bracket 28 on the frame I5. From the filament producing machine, fiity to several" hundred filaments can be extruded simultaneous- 1y, depending upon the type of extrusion head or of the forming the lower portions of hangers 3| that have pivotal connections 82 suspending them upon the upper portion of the frame I5. An arm 34 rigidly connected to the lower portion of each hanger extends laterally therefrom and is provided with a weight 35 adjustably mounted thereon by means of a set screw 30 passing therethrough into contact with the arm. The rolls thus mounted tend to swing toward the drum to confine and guide the filaments yieldably under pressure against the surface of the drum. These rolls 28 and 29 are disposed substantially on opposite sides of the drum slightly below the horizontal 'center line thereof, and the filaments 20 pass from the roll 20 over the upper. peripheral surface of the drum. They then pass downwardly between the roll 29 and drum through a tube 40 that is rigidly mounted on the frame I by means of a bracket 4| rigidly carried thereby.

The tube 40 is disposed substantially vertically and is partially flattened at its lower end to form a slot-like exit opening 42 (Fig. '7). The upper end portion of the tube has. formed thereon a hollow head 43 provided with a circumferential channel 45 which is surrounded by a collar 46 mounted by sweating it upon the head so as to provide an air-tight fit thereon in covering relation to the channel. Air directing ducts 41 lead from the channel 45 in a downward direction and open through the inner walls of the tube. A nipple 49 connected to the collar and communicating with the channel 45 is adapted to be connected to a suitable air pressure source (not shown) for the purpose of streaming air down-' wardly through the ducts 41 and downwardly through the tube.

Immediately below the lower end of the tube 40 a cutting device 50 is mounted by welding or otherwise securing a plate portion 5| thereof upon the frame I5. This plate also includes a stationary horizontal blade 52 rigidly carried thereby and has a pivot pin 53 mounted thereon to support a bell-crank 54. One arm 50 of the latter includes a knife 51 arranged to cooperate in shearing relation with the blade 52. The other arm 59 of the bell-crank is connected by means of a tension spring 60 to a lug 6| that is welded to the lower sideof the plate 5|. This spring normally holds the knife in open position. A setscrew 82 threaded through the lug 6| limits the pivotal movement of the bell-crank to prevent excessive opening of the knife. If desired. a com- 4 8|, on one end of a lever 84 that has an intermediate pivotal connection 88 securing it on an upright adjustable frame 51. The lower portion of the frame 81, which includes an upright bar 90, is pivoted upon one of the bearing members I 4 with its axis of pivoting coincidental with the axis of the driven shaft I2. An adjusting bolt 1 9| passes through the bar and through one of a series of openings 92 in an upright plate 94 that is rigidly mounted upon the apparatus frame I5. This arrangement provides for adjusting the frame 81 to the right or left, as viewed in Fig. 1, about the axis of rotation of the drum I0.

The end of the lever 04 opposite the mounting of the roll 80 has a pivotal connection 06 securing it to one end of an adjustable link 91, the other end of which is connected, as indicated at 90, to the outer end of an electric contact lever I00. The adjustable link includes opposite end heads IOI into which the shank of the link is screwthreaded in opposite directions so as to move the heads toward or away from each other, depending upon the direction of turning of the shank of the link. An intermediate portion of the contact lever I00 has a pivotal connection I02 securing it to the adjustable frame 01.

pression spring 63 can be mounted on thepin 53 a to maintain the bell-crank pressed against the plate 5| and in proper position to insure close contact between the blade 52 and knife 51 when they are moved in cutting relation. The terms blade and knife are employed to differentiate parts of the cutter structure although these elements perform substantially the same function.

The lever arrangement described above constitutes an actuating mechanism for making and breaking resilient contacts I04 and I05 of inverted U-shape which are mounted on the outer end of the lever I00 and on a bracket I00, respectively. The latter bracket I 06 is rigidly mounted upon the frame 81. The free end of the contact I04 is in the form of a horizontal finger I09 which is adapted to engage the other contact I05. In-

sulating blocks '2 and H3 forming end portions tion to the mains is controlled by a switch H8. 7

It will be observed that the levers 04 and I00 are so mounted that the degree of movement of the contact I04 on the outer end of the lever is greatly increased with respect to the movement of the roll 00 in response to movement of the larger portions of the tapered filaments 20 thereunder. When the larger portions of the filaments pass underneath the roll 80, the finger I09 is raised and in traveling upwardly it strikes a sloping under surface of a cam I20 that is formed upon the outer end portion of the insulating member 3. this movement until it is sprung outwardly and snaps over the upper edge of the cam to the positionv indicated in broken lines of Fi 3. As the larger portions of the filaments pass from beneath the roll the finger I00 drops against the contact I05 to the position shown in Fig. 4 and completes the electric circuit to energize the solenoid'l0 and to operate the knife 51, thereby severing the filaments 20. This action is rapidly consummated and the knife 51 is immediately reopened to such position that the next length of filaments to be cut continues past the knife until the thicker filaments again actuate the roll 80 to initiate a repetition of the operation described. In order that the filaments may not recoil or otherwise disarrange themselves before or after the cutting operation, air under pressure is streamed downwardly, through the tube 40 from the ducts 41. The action of the. air continuously draws the filaments toward the area of cutting.

The finger I09 continues.

The frame 81 can be adjusted to vary the distance from the point of contact of the roll 80 with the filament stock to the cutter. ment provides for cutting the filaments at the proper location and to provide for proper cuttin of filaments which have different lengths of tapered sections from those shown in the drawing.

It is to be understood that the group of filaments are supplied and fed to the drum ID in such manner that a thicker portion of any filament lies together with thicker portions of adjacent filaments. Thus the filaments as a group have successive thicker and thinner areas or sections. In the particular arrangement and adjustment of elements indicated in the drawings, the cutter severs the filament stock or group of filaments at their maximum thickness which, after cutting, constitutes butt ends I30. The smaller or thinner sections remain intact to be severed subsequently. As the successive sections of filaments are out they are gathered manually and bound by a thin band i3i of adhesive coated paper, Scotch tape,

or the like, at the location of the thinner portions.

Such adjust For the sake of clarity it is to be understood that tie section, that is, a double length section can be cut into two bristles of'tapered form. Double lengths of bristles are thus collected in bunches or bundles I34 and since their larger butt ends are arranged together and their thinner portions, which are later to be severed, are also together, such arrangement facilitates the maintenance of the bristles in proper relation. By grasping the thinner portions an operator can remove by combing out, or otherwise, any loose'bristle fragments or Other foreign matter that it may be desirable to discard. Likewise, the butt ends can be maintained in proper transverse relative alignment. Such control in handling the bristles would be difiicult in the event that they were originally cut to their final lengths, because loose tapered bristles require more than casual observation to discern their tapered form. Before the bristles are to be incorporated in a brush they are cut by shears I15, or otherwise, as indicated at I at their thinner portions. The cut is made through the binding band III 01' paper, or the like. A portion of the band thus remains upon the smaller tapered ends of the bristles after being cut to the length required for incorporation into the brushes, and, holds the bristles temporarily in bunched relation.

Although only one form of the invention has been shown and described in detail, it will be apparent to those skilled in the art that the invention is not so limited, but that various changes can be made therein without departing from the spirit of the invention or from the scope of the with thinner portions of all the cut sections bunched together, subsequently further cutting the sections to single length bristles while maintaining together the respective thinner and thicker portions preparatory :to incorporation. of the bristles into a brush.

2. In the manufacture of tapered synthetic bristies for brushes. the method which comprises cutting a filament, composed of successive linearly tapered sections, at the thicker filament portions to leave the thinner portions intact and further leaving the bristle sections in double lengths, gathering the cut filament sections and'binding them with their thinner portions together, and

cutting the bound filaments substantially midway between the section ends and at their thinner portions to produce single length tapered ibristles.

3. In the manufacture of tapered synthetic bristies for brushes, the method which comprises feeding recurrently tapered synthetic filaments as .a group along a predetermined path with the illsments as a group constituting a recurrently tapered mass of filament stock having aitemate thicker and thinner areas along its length, cutting the stock at the thicker areas to form doublelength bristle sections, gathering the doublelength bristle sections into bundles, binding the sections around their thinner portions with thicker portions thereof extending in opposite directions, and cutting the bound filaments substantially midway between the section ends and at their thinner portions to produce single-length tapered bristles.

4. In the manufacture of tapered synthetic bristies for brushes. the method which comprises cutting a filament, composed of successive linearly tapered sections, at the thicker filament portions to leave the thinner portions intact and further to leave the sections in double length bristle form, gathering the cut filament sections and binding them with a band of thin material secured around the thinner portions of the gathered filaments, cutting the bound filaments and the band thereby leaving sections of the band secured on end portions of the severed sections to hold them in assembled relation and in single-bristle length after the latter cutting operation.

5. In a method of preparing tapered synthetic bristles for incorporation into brushes, the steps which comprise continuously feeding recurrently tapered bristle stock along a predetermined course so that thicker and thinner portions of the stock pass successively a predetermined location, cutting the bristle stock at the thicker portions to form double length bristle sections, gathering the double length bristle sections and bundling them with the thinner portions of the sections together and the thicker portions together, and subsequently cutting the bristle sections at the thinner portions 'to form single length tapered bristles. JOHN J. GREGORY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED SIA'IES PATENTS Date Number Name 892,036 Emmert June 30, 1908 1,766,476 Zeitlin June 24, 1930 2,207,157 Neville et a1. July 9, 1940 2,341,823 Smith set. 15, 1944 

